[W126 Coupe] HELP! resistor vs. non resistor plugs

[Mister McGoo]

Tom;

I didn't see anyone reply to you. (Maybe I missed it.)

DO NOT USE RESISTOR PLUGS.  The resistance is already designed in.

Bosch specifies a spark gap of .032 throughout, not .040.

If you can't find Bosch plugs anywhere, you can use foreign plugs like 
Champion N 12 Y, or cross reference to NGK.

I'd try .035 +/- if you are burning oil.

If you have the AC Rapid Fire #4 plugs are you sure the cap doesn't unscrew 
from the lead stem?  Use pliers gently to try unscrewing.  I have never used 
them and have no information on them.  Obviously someone here has used them 
and thinks they are slicker'n snot.

If you have a Mercedes Benz Dealer in the vacinity, and if you are ever 
unsure of what you are being told, try asking the service people there.  
Don't be shy. Remember, you are a potential customer for them.  If they 
refuse to go out of their way to help find your answers, Mercedes Benz want 
to know about it!  I know.  (Just don't try it every second day.)

-Bellamy



>From: "Tom Oelsner" <toelsner at mindspring.com>
>Reply-To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>
>To: <mbcoupes at mbcoupes.com>
>Subject: [W126 Coupe] HELP! resistor vs. non resistor plugs
>Date: Wed, 21 Sep 2005 17:14:21 -0700
>
>This afternoon I replaced my plugs to see if I could smooth out my idle 
>that
>occasionally ran a tiny bit rough.  RH...you cannot use Rapid Fire #4 plugs
>as they have a one piece top that does not mate with the Bosch wires.  
>Also,
>AC Delco says do not use any anti seize lube on threads...
>
>So here is my problem.  The parts store did not have W9DC plugs in stock 
>but
>had WR9DC (resistor built in).  I queried him really hard about them and he
>said they would be fine and would not impact performance.  So I gapped them
>to .040 and put in new ignition wires (even though the old ones were only a
>year old, I broke one pulling it.  So I replaced all.).  Well the car idles
>really badly.  This is in spite of the fact that 3 of the older plugs were
>really fouled.  So my question is obvious.  Are the resistor plugs causing
>rough idle problems?
>
>Tom Oelsner
>90 560SEC
>
>
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